The process for making bread at home is time consuming and involves considerable skill. Yeast, sugars, flour, liquids and salt have to be combined in proper proportions to form a dough, which then has to be repeatedly kneaded and allowed to rise for precise periods of time. The dough then has to be baked and cooled. This process takes many hours to complete and involves careful monitoring of time and temperature. Therefore, it is normally difficult for inexperienced people to make bread successfully at home.
Automatic bread making machines were developed to simplify the process of making bread at home. Generally, bread makers are self-contained units consisting of a kneading/baking chamber, a motor driving a kneading blade, a heating unit, a fan and a control unit to drive the various electrical and mechanical components.
Processes for making bread in a bread-maker are disclosed, for example, in Nakakura, et al., U.S. Pat. No. 4,885,176 and Horiuchi, et al., U.S. Pat. No. 4,903,588. Generally, a user adds raw bread ingredients to the kneading/baking chamber of the bread maker and then inputs instructions to a control panel to specify the size, type etc. of bread being made. The control unit includes a microprocessor and uses these instructions to select the parameters required to produce the bread. The ingredients are first mixed into a dough and kneaded by actuating a motor to rotate the kneading blade within the baking chamber. Next, the dough is fermented and degassed, usually for several cycles, and then baked. When baking is completed, the user either removes the bread from the machine for cooling or the heater is deactivated and the bread cools inside the machine.
While bread makers have greatly simplified the process for making bread at home, the resulting bread can be of inferior quality due to shortcomings in the processes used by the bread makers. For example, the kneading/baking chamber in a bread maker is generally square or rectangular. During mixing and kneading, ingredients can be lodged into the corners of the chamber by the constant force of the kneading blade and will not be properly incorporated into the dough. Also, the simple cyclic rotational movement of the kneading blade within the chamber does not provide for the randomness and thoroughness of hand kneading. In other words, a portion of the dough sticks to or "floats" on the kneading blade, resulting in an inconsistent dough that will not produce optimum quality bread with a fine cell structure.
Temperature control within the bread maker may also affect the quality of the bread. For example, if the temperature is too low after fermentation or rising, the dough will not properly release gas during degassing and the texture and height of the resulting bread may suffer. Further, since bread makers are relatively compact, the heating element must be placed within close proximity of the baking chamber, making it difficult to consistently ensure good crust browning and even inside cooking using a conventional single temperature bake cycle. Also, if the user does not promptly remove the bread after baking is complete and the heater is deactivated, steam produced in the baking chamber may condense back into the bread, impairing both its appearance and taste.
Various other patents propose bread makers in an attempt to overcome these and other problems. For example, Ojima, et al., U.S. Pat. No. 4,538,509 and Hirota, et al., U.S. Pat. No. 4,762,057, disclose bread makers with an insulated water tank separate from the kneading/baking chamber. The temperature of the water added to the tank is used to regulate the temperature inside the machine. Ojima, U.S. Pat. No. 4,776,265 and Nakakura, et al., U.S. Pat. No. 4,885,176, disclose bread-makers with a separate yeast-adding device. While these features may contribute to improving the quality of bread produced, they also introduce additional electrical and mechanical elements and complicate the control processes of the machines. Thus, the machines are bulkier and more expensive to manufacture. Further, forcing the user to add ingredients such as yeast and water separately complicates the use of the machine.
Thus, there remains a need for an improved process to enable an automatic bread maker to consistently produce high quality bread without introducing additional complex elements to the machine or the user.